Demonstrators protest outside the Israeil Embassy in west London July 26, 2014. (Reuters / Luke MacGregor)

Tens of thousands of demonstrators have marched across London to protest Israel’s Operation Protective Edge, carrying signs reading “Gaza: End the siege.” Rallies also took place in France, Ireland and Israel as the Palestinian death toll surpassed 1,000.

Metropolitan Police placed the number of participants in London at around 45,000, The Independent reported. The demonstration, which began near High Street Kensington, passed the Israeli Embassy and eventually reached Parliament Square. Participants chanted, “Long live Gaza; long live Palestine” as they marched.

Several high profile speakers addressed the crowd, including Labour MP Diane Abbot, who said the participants were there to show solidarity with the people of Gaza.

Saturday’s march occurred in the context of a 12-hour ceasefire between Israel and Hamas that began at 8 a.m. local time. Israel said that while it would adhere to the ceasefire, it would also continue to look for tunnels potentially used by Hamas militants.

Over 100 bodies were recovered from the rubble in Gaza on Saturday, many of which were partially decomposed, Palestinian health official Ashraf al-Kidra said.

Israel launched a major air campaign in Gaza on July 8 and later sent ground troops into Hamas-ruled territory.

According to the Israel Defense Forces (IDF), Operation Protective Edge is aimed at halting Palestinian rocket fire and destroying Hamas’ cross-border tunnels. The conflict has been ongoing for 19 days, with Israel’s Iron Dome intercepting the majority of rockets fired from the Gaza Strip.

In addition to the loss of Palestinian lives, at least 40 Israeli army soldiers have been killed.

“Our [British] aid and arms are helping to kill these innocent people in Gaza,” he said. Last year, Britain sold some $10.7 million worth of arms to Israel.

Other cities across the UK also staged protests on Saturday – including Oxford, Cardiff, and Edinburgh. A similar, smaller protest marched on Downing Street a week ago, with less than half the number of protesters taking part.

Paris rally takes place despite ban, dozens arrested

Hundreds of demonstrators also took to the streets of Paris on Saturday, clashing with police after a ban imposed by French authorities was defied.

Police said that 50 people were arrested over the course of the day. French Interior Minister Bernard Cazeneuve said that organizers would be held responsible. He stressed that only five out of approximately 300 protests in the country had been banned, and that prohibiting the mass action was the exception rather than the rule.

The protest had been banned due to police fears over the security of the march route, France 24 reported. A rally on July 22 finished with hundreds of protesters looting shops, burning cars and attacking a synagogue. However, one of its organizers said the decision was political.

A Reuters photographer witnessed one Israeli flag being burnt, according to the agency. However, organizers denied accusations of anti-Semitism.

Seven foreign ministers met in Paris on Saturday and called for an extension of the ceasefire. France issued a joint statement with the US, Britain, Germany, Italy, Qatar, and Turkey, as well as the EU’s deputy foreign minister.

Meanwhile, some 2,000 people were permitted to march peacefully in Marseilles.

Demonstrations in Ireland, Israel and Canada

Thousands also turned up in Dublin, with Palestinian and Irish speakers addressing the crowd from a makeshift stage near the Israeli embassy.

Canada’s Toronto saw two protests running simultaneously: to support Israel and against its operation in Gaza. Hundreds of people came to both rallies and as the two met – divided by a police cordon – tensions spiked with insults flying.

Protests demanding an end to Israel’s operation in Gaza have been gripping the world for over a week. Thousands have also been taking part in demonstrations in the West Bank, since Hamas leaders called on Ramallah to come out for its cause. Rallies there have been ongoing for two nights, with Israel using “riot dispersal means” to break them up. Six people have been killed since the night demonstrations began, medics and witnesses told the Guardian on Friday.